I love the Sorter and, together with bookmarklets, it really sets DT apart from the competition.
However, it whetted the appetite and made me want more: I would like to be able to include documents, in addition to groups, in the nine “zones” of the sorter. Upon dragging an object onto a zone containing a document, rather than a group, I would like that object to be appended to the corresponding document.
But one can create a rich text note that’s linked to a document. Now, you can add into that rich text note links (e.g., Item Links or, for PDFs, Page Links) to any other document in your database(s), and/or links to external files in the Finder (e.g., by Command-Option-drag of a Finder file into the cursor insertion point in the rich text document).
In that way you can create a searchable and hypertext-linked list of all the files ‘attached’ to a document (along with your notes and comments, if you wish). Command-click on a link to a document in a database and it will be opened in a new tab, available for viewing. Click on a link to an external file in the Finder and it will be opened under its parent application.
Eric has created a smart template that will automatically generate a new rich text note linked to any selected document. This and a number of other smart templates will be included in the upcoming public beta 8 of DT Pro and DT Pro Office.